The present invention relates to illumination control of a turn signal for a vehicle, and more particularly, to a turn signal illumination controller that automatically cancels an illuminated turn signal indicator.
Turn signal indicators are arranged on an outer surface of a vehicle to notify others that the vehicle will turn right or left at an intersection or change lanes. A turn switch lever, which is arranged near the steering wheel, is tilted to the right (clockwise direction) to flash a right turn signal indicator, and tilted to the left (counterclockwise direction) to flash a left turn signal indicator.
The vehicle includes a turn signal illumination controller that controls the illumination and cancellation of the turn signal indicators in accordance with the operation of the turn switch lever. A widely used mechanical turn signal illumination controller switches a turn signal indicator from an illuminated state to a cancelled state by mechanically activating and deactivating a switch contact in cooperation with the movement of the turn switch lever. The operation of the mechanical turn signal illumination controller when the vehicle is turned to the right will now be described. The driver, for example, tilts the turn switch lever to the right from a neutral position and rotates the steering wheel to the right (clockwise rotation). When tilted to the right, the turn switch lever activates a micro switch. Further, a holding mechanism holds the turn switch lever at a right tilt position and keeps the micro switch activated. As long as the micro switch remains activated, the turn signal indicator continues to flash. Then, when the steering wheel is rotated back to the left (back rotation), the holding mechanism releases the turn switch lever in cooperation with the back rotation. This returns the turn switch lever to the neutral position from the right tilt position thereby deactivating the micro switch and cancelling the turn signal indicator.
Japanese Laid-Open Patent Publication No. 11-70833 discusses an auto-cancellation type turn signal illumination controller that automatically cancels a turn signal indicator without cooperating with the turn signal switch lever. The auto-cancellation type turn signal illumination controller includes a rotational angle sensor, which monitors the rotational angle of the steering wheel. When the steering wheel is rotated back toward its original position while the turn signal indicator is flashing, the turn signal illumination controller automatically cancels the turn signal indicator when the rotational angle sensor detects that the angle of the back rotation has reached a cancellation angle.